fix potential refleak in PyFloat_AsDouble (closes #23590)

Lib/test/test_float.py

@@ -8,6 +8,7 @@ import operator
 import random
 import fractions
 import sys
+import time
 
 INF = float("inf")
 NAN = float("nan")
@@ -164,6 +165,11 @@ class GeneralFloatCases(unittest.TestCase):
         self.assertAlmostEqual(float(FooUnicode('8')), 9.)
         self.assertAlmostEqual(float(FooStr('8')), 9.)
 
+        class Foo5:
+            def __float__(self):
+                return ""
+        self.assertRaises(TypeError, time.sleep, Foo5())
+
     def test_is_integer(self):
         self.assertFalse((1.1).is_integer())
         self.assertTrue((1.).is_integer())

Objects/floatobject.c

@@ -271,6 +271,7 @@ PyFloat_AsDouble(PyObject *op)
     if (fo == NULL)
         return -1;
     if (!PyFloat_Check(fo)) {
+        Py_DECREF(fo);
         PyErr_SetString(PyExc_TypeError,
                         "nb_float should return float object");
         return -1;